Russia called on Azerbaijan to unblock the key road leading to the Lachin Corridor, according to a statement by the Russian Foreign Ministry, but Baku has not responded positively.

The issue is becoming a major irritant for Russia, which wants to maintain good relations with both Azerbaijan and Armenia, two small former Soviet states in the Caucasus region.

For the past month, Azerbaijanis claiming to be environmental activists have blocked transport along the Lachin Corridor the only road linking Karabakh to Armenia, in what Yerevan has called a government-endorsed blockade.

Russian Foreign Minister Sergei Lavrov spoke to Azerbaijani counterpart Jeyhun Bayramov and "stressed the need for a swift and complete unblocking of traffic through the Lachin Corridor," the Russian foreign ministry said in a statement.

Bayramov dismissed the allegations of a roadblock and a humanitarian crisis in the enclave, saying dozens of cars and ambulances used the corridor every day, according to an Azerbaijani statement cited by Russia's Interfax news agency.

Baku says the protesters have legitimate concerns over illegal Armenian mining in the area.

"In this context, the need to fulfill the just demand of the protesters was noted," said the Azerbaijani statement.

Officials in Yerevan have grown increasingly angry at Russia - formally an ally through a mutual self-defense treaty - for not doing more to end the blockade, especially since Russian peacekeepers are deployed in the corridor. Russia blamed Armenia last week for a breakdown in bilateral peace talks with Azerbaijan.

Azerbaijani President Ilham Aliyev said in October that clearing mines that have been planted by Armenia on occupied Azerbaijani territories will take nearly 30 years and cost $25 billion.

Baku also highlighted that Yerevan is not fulfilling its obligations under a statement signed after the Karabakh war in 2020, including the withdrawal of Armenian armed forces from Azerbaijani territory, as it abuses the Lachin road for military provocations and obstructs the opening of all transport communications in the region.

Relations between the former Soviet republics of Armenia and Azerbaijan have been tense since 1991 when the Armenian military illegally occupied Karabakh, a territory internationally recognized as part of Azerbaijan, and seven adjacent regions.

Clashes erupted on Sept. 27, 2020, with the Armenian Army attacking civilians and Azerbaijani forces, violating several humanitarian cease-fire agreements.

During the 44-day conflict, Azerbaijan liberated several cities and around 300 settlements and villages that had been occupied by Armenia for almost 30 years.

The fighting ended with a Russian-brokered agreement on Nov. 10, 2020, which was seen as a victory for Azerbaijan and a defeat for Armenia.

However, the cease-fire has been broken several times since then.